by Donovan Slack and Paul Singer, USA TODAY

by Donovan Slack and Paul Singer, USA TODAY

WASHINGTON - Last summer, Sen. Mark Warner, D-Va., embarked on what his office trumpeted as a four-day, 1,000-mile trip across his state, with press releases noting he "woke up early to hit the road," making stops at a minor league ballpark, a craft brewery and a Roanoke rail yard, among others.

But for several hundred of those miles, Warner was not hitting the road - he was flying a chartered plane at a cost to taxpayers of $8,500.

Warner was one of two dozen U.S. senators who flew taxpayer-funded charter airplanes to, from or around their home state last year at a total cost of just under $1 million, according to a USA TODAY analysis of Senate spending records compiled by the nonpartisan Sunlight Foundation.

Senators pay for their official duties from taxpayer-funded accounts set aside for them to cover costs of staff, travel, office supplies and the like. The rules allow them to use these accounts to pay for charter aircraft for official travel when commercial flights "are not such that reasonable schedules may be kept." Senators decide which way to travel, and some eschewed private jets in favor of flying commercial or simply driving.

Warner's 1,000-mile trip took him to the far reaches of western Virginia, which is pretty remote territory with no commercial airports. But a month earlier, Virginia's other U.S. senator, Tim Kaine, made a swing to the same corner of the state by car; his travel cost taxpayers $691. Both Warner and Kaine are Democrats representing the state that is closest to the U.S. Capitol.

"Sen. Warner is a road warrior, and he insists on a schedule that goes from dawn to dusk," said Kevin Hall, Warner's spokesman. "He spent 75 days on the road in Virginia last year, and that does not include events here in Northern Virginia."

Hall said the road trip involved 25 public events across the state. "Using a plane to get from one end of the state to the other freed-up more than 12 hours of driving time, and this allowed us to schedule several additional events and create more opportunities to meet with our Virginia constituents."

Many of the senators reporting charter flights hail from large and sparsely populated states. For instance, Republican John Barrasso of Wyoming reported charter flights totaling $83,000 in 2013, including a $3,700 trip to Cowley, Wyo., a town of fewer than 1,000 people on the state's northern border. His colleague Mike Enzi, also a Republican, spent just under $32,000 on charter flights last year. Both offices said the geography of the state required charter travel to reach constituents.

But the top two charter fliers in 2013 were Sens. Charles Schumer and Kirsten Gillibrand, both Democrats of New York - a large but more densely populated state with a lot of commercial transportation options.

Schumer on several occasions spent more than $5,000 from his office account to charter planes between New York City and Albany, Buffalo and Rochester, even though cheaper commercial flights and trains link the cities. Gillibrand regularly chartered flights from Washington to places in New York with multiple transportation options.

Aides to Gillibrand and Schumer said their schedules precluded them from traveling by other means. Schumer spokesman Matt House tried to dispel any notion that the senator was charging taxpayers for high-flying luxuries.

"It is not possible to keep this rigorous a schedule by flying on commercial airlines alone, so he also travels on a small, four-seat propeller plane with no bathroom that's not even big enough to stand up in," House said.

In some cases senators representing the same state split on whether to fly charters.

For instance, Sen. Mary Landrieu, a Democrat, spent $47,000 on charter flights in 2013, including a $5,500 round trip flight between New Orleans and Lake Charles, La., 200 miles to the west. Landrieu spokesman Matthew Lehner said chartering planes allowed the senator to reach more areas of the state more quickly.

"This alleviates the need for multi-day stopovers and maximizes the senator's interaction with her constituents," he said.

But Republican David Vitter, the other Louisiana senator, reported no charter flights. His spokesman, Luke Bolar, said the senator always flies commercial and drives rather than flies around Louisiana.

In Texas, Sen. Ted Cruz, a Republican, spent about $18,000 on charter flights around the state. "We will sometimes use a charter when there is not a commercial flight available to get him between official events scheduled in the state," Cruz spokeswoman Catherine Frazier said.

"As you know, Texas is a rather large state, and we do our best to maximize his time with constituents in different regions," Frazier said. But the Lone Star State's other senator, Republican John Cornyn, used only commercial transportation.

In West Virginia, Sen. Joe Manchin recorded no charter flights in 2013, while fellow Democratic Sen. Jay Rockefeller, who announced at the beginning of last year that he would not run for re-election, took $91,000 worth of charter flights. Rockefeller's office did not respond to requests for comment on this story.

Overall, 14 Republicans, nine Democrats and one independent reported charter flights in 2013, but Democrats spent $638,000 of the $920,000 total spent on charters.